U.S. Pat. No. 3,660,651 issued 1972 to Miles, the disclosure of which is incorporated herein by reference, teaches an adjustable downlight assembly comprising a lamp holder housing suspended in a back housing in a ceiling cavity by a scissor/toggle type linkage, extension and contraction of which permits the lamp to be pulled down and pushed up, respectively, between lower and upper positions exposed below the housing and relatively concealed within the housing, respectively, for lamp aiming and different lighting effects.
The prior lamp holder housing may also be rotated about a vertical axis and the shade/reflector pivoted about a horizontal axis.
However, Miles does not teach the concept of modularity enabling any selected variable number of closely similar downlight assemblies to be mounted in a single back housing in a ceiling cavity or, means permitting the selective addition and removal of a downlight assembly by ready access only from below the ceiling while the back housing remains mounted in the ceiling cavity. In addition, Miles does not make provision for an individual power supply, such as a transformer or ballast, incorporated with each module assembly, as extremely desirable for achieving modularity. Furthermore, Miles does not teach any means built in a downlight assembly for determining a precise angle of rotation about the vertical or horizontal axes for ease of aiming adjustment and calibration, nor for adequately limiting the pivotal movement of the lamp holder housing independently of engagement with the back housing or cabling.